diff --git a/audio/5.0/IStreamIn.hal b/audio/5.0/IStreamIn.hal
index b042960..e15b034 100644
--- a/audio/5.0/IStreamIn.hal
+++ b/audio/5.0/IStreamIn.hal
@@ -169,6 +169,10 @@
     /**
      * Specifies the logical microphone (for processing).
      *
+     * If the feature is not supported an error should be returned
+     * If multiple microphones are present, this should be treated as a preference
+     * for their combined direction.
+     *
      * Optional method
      *
      * @param Direction constant
@@ -180,6 +184,10 @@
     /**
      * Specifies the zoom factor for the selected microphone (for processing).
      *
+     * If the feature is not supported an error should be returned
+     * If multiple microphones are present, this should be treated as a preference
+     * for their combined field dimension.
+     *
      * Optional method
      *
      * @param the desired field dimension of microphone capture. Range is from -1 (wide angle),